Convertible directional control valve



Jan. 30, 1968 v. P. DONNER 3,366,134

CONVERTIBLE DIRECTIONAL CONTROL VALVE Filed Oct. 11, 196 5 5 Sheets-Sheet 1 INVENTOR VERNE P. DONNER ATTORNEY Jan. 30, 1968 v. P. DONN-ER 3,366,134

CONVERTIBLE DIRECTIONAL CONTROL VALVE Filed Oct. 11, 1965 s' Sheets-Sheet 2 INVENTOR VERNE P. DONNER ATTORNEY Jan. 30, 1968 w v. P. DONNER 3,366,134

NNNNNN OR A T T O R N EY United States Patent 3,366,134 CONVERTIBLE DIRECTIONAL CONTROL VALVE Verne P. Donner, Palatine, IlL, assignor to Deltrol Corp., Bellwood, 11]., a corporation of Delaware Filed Oct. 11, 1965, Ser. No. 494,603 2 Claims. (Cl. 137-469) ABSTRACT OF THE DISCLOSURE A directional control valve has a body, a spool bore, a pressure passage intersecting the bore at a point intermediate its ends, a pair of motor passages intersecting the bore at points on opposite sides of the point of intersection of the pressure passage and leading outwardly through the body to terminate at ports, and a branched exhaust passage intersecting the bore at points on opposite sides of the point of intersection of the pressure passage and outwardly of the points of intersection of the motor passages. A spool having two working annuli is shiftable in the bore between a first working position in which one annulus affords communication between the pressure passage and one motor passage while the other affords communication between the other motor passage and the associated exhaust passage branch and a second position in which the functions of the annuli are reversed. The motor passages extend outwardly and laterally across the points of intersection of the associated exhaust passage branches so that the ports are in line with the exhaust passage branches and there are walls separating the motor passages from the associated exhaust passage branches that face the ports. Vent passages which are in line with the ports are provided through these walls; and there are removable threaded plugs to block the vent passages which are insertable and removable through the ports.

This invention relates to directional control valves; and it resides more particularly in a valve of the shiftable spool type that is convertible between three-way and fourway operation without necessitating replacement of the valve spool, such convertibility being provided by means of at least one vent passage and removable plug therefor that afford selective communication between an unused motor passage and an exhaust passage during three-way operation.

Conventional four-way directional control valves include two motor passages and a spool with two working annuli that is shiftable in both directions from a neutral position. When the spool is shifted in one direction, one of the annuli affords communication between a pressure passage and one of the motor passages so that fluid under pressure is directed outwardly therethrough. The other annulus at the same time affords communication between the second motor passage and an exhaust passage to dispose of fluid returned through the second motor passage. When the valve spool is shifted in the other direction, the operation reverses and returned fluid is admitted through the first motor passage while fluid under pressure is directed through the second. Usually, such valves have what is known as tandem center operation in which, when the spool is in its neutral position, there is a through passage through the valve body so that pumped fluid flows through the valve and to a reservoir. In some cases, however, a closed center operation is provided in which there is no through passage and pumped fluid is directed against a relief valve when the spool is in neutral position.

It is often desirable to convert a four-way valve to three-way operation. In such three-way operation, only one of the motor passages, which can be referred to as a work passage, is used and the other is plugged. When the valve spool is shifted in one direction, fluid under 3,365,134 Patented Jan. 30, 1968 pressure passes outwardl through the work passage, and when the spool is shifted in the other direction fluid is returned through the work passage. To eflect a conversion from four-way to three-way operation, it has heretofore been necessary to replace the conventional four-way spool with a three-way spool having only one working annulus, associated with the work passage. If this were not done, when the valve was shifted to admit returning fluid through the work passage pumped fluid would be directed into the plugged, unused motor passage and trapped there, with undesirable effects. Substituting one form of spool for another is a relatively complex procedure and requires a considerable amount of time. Further, valve spools are quite expensive and this prior practice made it necessary for dealers and users to purchase and stock two forms of spools to provide for the desired convertiblity of operation.

It is the general object of this invention to provide a directional control valve in which conversion between three and four-way operation may be had without replacement of the valve spool. With a valve formed according to the invention, conversion can be effected for either tandem or closed center operation.

It is another object of the invention to provide a valve in which conversion can be accomplished easily and quickly without necessitating dismantling the valve or removing it from service for a prolonged period.

It is a further object of the invention to provide a valve in which either of two motor passages may be used a a work passage for three-way operation.

It is still another object of the invention to provide a valve having the foregoing advantages which is strong and long wearing and relatively simple and inexpensive to manufacture and use.

Other objects and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings, forming a part hereof, in which there is shown, by way of illustration and not of limitation, a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a view in cross-section, taken along the plane 1-1 shown in FIG. 2, of a directional control valve formed according to the invention,

FIG. 2 is a view in cross-section of the valve of FIG. 1, taken along the plane 22 shown in FIG. 3,

FIG. 3 is a view in cross-section of the valve of FIG. 1, taken along the plane 3-3 shown in FIG. 2,

FIG. 4 is a fragmentary view in cross-section of the valve of FIG. 1, taken along the plane 44 shown in FIG. 3,

FIG. 5 is a fragmentary view in cross-section of the valve of FIG. 1, taken along the plane 55 shown in FIG. 1,

FIG. 6 is a fragmentary view in cross-section of the valve of FIG. 1, taken along the plane 6-6 shown in FIG. 1, and

FIG. 7 is a view in cross-sction of the valve of FIG. 1, taken along the plane 7-7 shown in FIG. 7.

The valve shown in the drawings is relatively conventional in overall configuration, and includes a body 1, an inlet port 2 leading to a relatively large pressure chamber 3, having therein a boss 3a, and a spool bore 4 within which is disposed a cylindrical, axially shiftable spool 5. A branched exhaust passage designated generally by the reference numeral 6 intersects the bore 4 at several points as will be described, and leads outwardly of the body 1 through an exhaust port 7 substantially opposite the inlet port 2.

A first, or through, passage 8 leads inwardly from the pressure chamber 3 to intersect the bore 4 nearer its left end as seen in FIGS. 1 and 2. The portion of the chamber 3 which lies immediately to the right of and at the level of the boss 3a, as seen in FIG. 2, serves as a relief passage, numbered 9, which intersects a cylindrical, stepped relief bore 16 within which is disposed a conventional relief valve indicated generally by the reference numeral 11. The inner end of the relief valve 11 is received in a continuation of the bore formed in the boss 30. A relief branch 12 of the exhaust passage 6 also intersects the bore 10 so that any fluid passed through the relief valve 11 as the result of excessive pressure may be exhausted to a reservoir. The relief valve 11 can of course be selected to open at any desired pressure in accordance with usual practice.

As can be seen in FIGS. 3 and 4, a check valve port 13 leads from the upper part of the pressure chamber 3, over the passage 9, to a check valve bore 14 within which is disposed a poppet-type check valve 15 which lies above and generally parallel to the relief valve 11. A pressure passage 16 intersects the bore 14 and leads generally downwardly, as can be seen in FIG. 7, to intersect the spool bore 4. The check valve 15 includes a hollowed plug member 17 threaded into the body 1 and a hollowed, cylindrical poppet 18 that is provided with radial ports 19 and is axially slidable in the bore 14. A compression spring 20 urges the poppet 18 inwardly to a seated position where it closes off the check port 13. When suflicient pressure is developed in the chamber 3, the poppet 18 will be moved, against the spring 29, to the right as seen in FIG. 4 so that fluid under pressure may flow through the pressure passage 16 to the bore 4. In the event of a reverse flow through the passage 16, however, fluid will enter the poppet 18 through the ports 19 and act on the rear side of the poppet 18 to hold it against its seat closing the port 13.

The exhaust passage 6 includes three other branches which intersect the bore 4, all to the left of the relief branch 12 as seen in FIG. 2. These include a work branch 21 closest to the branch 12 but on the opposite side of the pressure passage 16, a through branch 22 to the left of the branch 21 and on the opposite side of the through passage 8, and a third branch 23 to the left of the branch 22, which branch 23 plays no part in the present invention but is useful for other modes of operation.

As can be seen most clearly in FIG. 1, a left motor passage 24 intersects the bore 4 between the pressure passage 16 and the exhaust work passage 21 and curves in an S-path to the left and outwardly to open through the valve body 1 at a left motor port 25. A right motor passage 26 intersects the bore 4 between the pressure passage 16 and the exhaust relief branch 12 and curves in an S-path to the right and outwardly to open through the body 1 at a right motor port 27.

A first, or left, threaded vent passage 28, seen in FIGS. 1 and 5, leads directly inwardly from the curved portion of the left motor passage 24 to the exhaust work passage 21, and a threaded plug 29 is normally threaded into the passage 28 to seal it off. The outer face of the plug 29 is provided with a hexagonal socket or other appropriate tool engaging means so that the plug 29 may be easily inserted or removed by means of a tool inserted through the left motor port 25, which is in line with and substantially directly outwardly of the plug 29. Similarly, there is a right threaded vent passage 30, seen in FIGS. 1 and 6, leading from the right motor passage 26 to the exhaust relief branch 12. A right threaded plug 31 normally blocks off the passage and is provided with a socket so that it may be inserted or removed through the right motor port 27 which is in line with and lies substantially directly outwardly from the plug 31.

The spool 5 is slidably disposed in the bore 4 with its right end, as seen in FIGS. 1 and 2, extending outwardly through the valve body 1 and being apertured to be connected to a conventional operating lever (not shown). The left end of the spool 5 also extends outwardly of the body 1 and is connected to a conventional centering spring assembly mounted on the body 1 that is designated generally by the reference numeral 32, which assembly 32 serves in usual fashion to return the spool 5 to a centered or neutral position when 'it is shifted axially to either side.

The spool 5 is provided with three reduced portions or annuli, a through annulus 33 located toward the left end of the spool 5 as seen in FIGS. 1 and 2, a left working annulus 34 and a right working annulus 35.

With the plugs 29 and 31 in place, the valve as shown in the drawings is adapted for normal four-way, tandem center operation with, for example, the ports 25 and 27 connected to opposite ends of a double-acting hydraulic cylinder. In the drawings the spool 5 is shown in its neutral position. In this position, the through annulus 33 affords communication between the through passage 3 and the through exhaust branch 22 so that fluid under pressure passes directly through the valve and into a reservoir. The working annuli 34 and 35 are spaced on opposite sides of the pressure passage 16 so that no fluid may pass therethrough. Should the spool 5 now be shifted to the left, the through annulus 33 will be moved to the left to block off communication between the passages 8 and 22. Fluid under pressure will, therefore, be diverted through the check valve 15 and into the pressure passage 16. At approximately the same time, the right working annulus 35 will be moved to afford communication, through the bore 4, between the passage 16 and the right motor passage 26 so that fluid under pressure will be moved outwardly through the passage 26 and right working port 27. The left working annulus 34 will be moved to afford communication, through the bore 4, between the left motor passage 24 and the exhaust working branch 21 so that fluid may be returned through the passage 24 to a reservoir. Similarly, if the spool 5 is shifted to the right, fluid under pressure will be admitted to the left motor passage 24 and return fluid will be admitted through the right motor passage 26.

Should it now be desired to convert the valve to threeway operation, using, for example, the left motor passage 24 as the work passage, the right conversion plug 31 is removed opening the passage 30 and the right motor port 27 is then plugged so that it is inoperative. The left motor port 25 will, for example, be connected to a singleacting hydraulic cylinder. When the spool 5 is now shifted to the right, fluid under pressure will be admitted to the left motor passage 24 as before. Since the right motor port 27 is plugged, however, there will be no returning fluid. When the spool 5 is then shifted to the left, fluid will be returned through the left motor passage 24 and the exhaust work branch 21. In this position, however, fluid under pressure will be admitted to the right motor passage 26 which would ordinarily be blocked with the right port 27 plugged. Since the conversion plug 31 has been removed, however, such fluid may pass directly through the vent passage 30 to the exhaust branch 12 and to the reservoir to avoid blockage and an undesirable build-up in pressure. Fluid may flow through the branch 12 regardless of the position of the spool 5 since the branch 12 has, as can be seen in FIG. 6, a major vertical dimension greater than the diameter of the bore 4 so that fluid can flow around the spool 5.

Similarly, the valve may be converted to three-way operation using the right-hand motor passage 26 as a working passage. In this case, the right-hand plug 31 is left in place but the left plug 29 is removed and the left motor port 25 is plugged. Pumped fluid can then flow through the passage 30 and out the exhaust branch 21. As can be seen in FIG. 5, the branch 21 is also larger than the bore 4 so that fluid can flow around the spool 5 regardless of its position.

In all phases of the operation, the relief valve 11 affords protection against excessive pressure. Fluid passed through the valve 11 can always flow through the exhaust branch 12 regardless of the position of the spool 5 since,

again, the branch 12 has a major vertical dimension greater than the diameter of the bore 4.

The through spool annulus 33 affords tandem center operation in which there is a through passage for fluid under pressure when the valve is in neutral position. Closed center operation can be provided simply by substituting a spool in which there is no through annulus so that fluid under pressure will be diverted against the relief valve 11. It will be appreciated that conversion between three and four-way operation can also be accomplished in the same manner with such a closed center arrangement,

Thus, it can be seen that the valve of this invention provides for conversion between three and four-way operation, -for either tandem center or closed center circuitry, Without changing the valve spool in either case. Conversion is accomplished simply by removing one of the plugs 29 or 31, both of which are easily accessible through the motor ports 25 and 27 which lie substantially directly outwardly of them. Providing the threaded vent passages 28 and 30 is relatively simple from the manufacturing standpoint since each passage is straight and in a substantially direct line between a motor port and an exhaust branch. The passages and the threaded plugs 29 and 31 provide, therefore, an extremely inexpensive but effective means for eflecting the desired conversion.

The S curvature of the passages 24 and 26 is very advantageous in the preferred embodiment shown, since this makes it relatively simple to have the ports 25, 27 and passages 28, 30 in line. Without curved motor passages it might be considerably more diflicult to properly locate the vent passages.

Although the embodiment of the invention shown herein is preferred, it Wiil be apparent that modifications may be made therein without departure from the invention. It would be possible, for example, to provide only one vent passage and plug, which would still afford convertibility but would require always using the same one of the motor passages as a Work passage for three-way operation. In view of possible modifications, it is not intended that the invention be limited by the embodiment shown herein, or in any other way, except insofar as limitations appear specifically in the following claims.

I claim:

1. An improved directional control valve having a body, a spool bore in the body, an exhaust passage intersecting the bore at at least one point, a pressure passage intersecting the bore, a pair of motor passages intersecting the bore and leading therefrom to terminate at ports leading outwardly of the body, and a spool having two spaced Working annuli that is axially shiftable in the bore between a first working position in which one annulus aifords communication between the pressure passage and one motor passage while the other annulus affords communication between the other motor passage and the exhaust passage and a second working position in which said one annulus affords communication between said one motor passage and the exhaust passage while said other annulus aflfords communication between said other motor passage and the pressure passage; wherein the improvement resides in at least one of the motor passages being arranged to extend laterally across the point of intersection of the exhaust passage with the bore and outwardly to define a wall between said motor passage and the exhaust passage which faces the port of said motor passage, there being a vent passage extending through said wall that is in line with said port and a removable plug selectively blocking said passage that faces the port and is insertable and removable therethrough.

2. A valve according to claim 1 wherein the exhaust passage is branched to intersect the bore at two points on opposite sides of the point of intersection of the pressure passage, each branch of the exhaust passage being associated with a respective motor passage; and both motor passages lead laterally across the points of intersection of their respective exhaust passage branches and outwardly to define walls which face the respective ports; and each wall is provided with a vent passage in alignment with the respective port; and there is a removable plug selectively blocking each vent passage that is insertable and removable through the associated port.

References Cited UNITED STATES PATENTS 2,651,324 9/1953 Hodgson et al. 137-596.12 2,718,240 9/1955 Margrave 137-625.69 2,745,433 5/1956 Schneider 137-596.13 2,868,227 1/1959 Stephens 137-59613 HENRY T. KLINKSIEK, Primary Examiner. 

